/*
* Copyright (c) 1998-2011 Caucho Technology -- all rights reserved
*
* This file is part of Resin(R) Open Source
*
* Each copy or derived work must preserve the copyright notice and this
* notice unmodified.
*
* Resin Open Source is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Resin Open Source is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, or any warranty
* of NON-INFRINGEMENT. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License
* along with Resin Open Source; if not, write to the
*
* Free Software Foundation, Inc.
* 59 Temple Place, Suite 330
* Boston, MA 02111-1307 USA
*
* @author Scott Ferguson
*/
package com.caucho.vfs;
import com.caucho.util.NullIterator;
import java.io.IOException;
import java.util.Iterator;
/**
* This is the service provider's interface for a stream supported by
* the VFS.
*/
public class StreamImpl {
protected static NullPath _nullPath;
private static final byte _newline[] = new byte[] {(byte) '\n'};
protected Path _path;
/**
* Returns the stream's natural newline character.
*/
public byte []getNewline()
{
return _newline;
}
/**
* Returns true if the stream implements skip.
*/
public boolean hasSkip()
{
return false;
}
/**
* Skips a number of bytes, returning the bytes skipped.
*
* @param n the number of types to skip.
*
* @return the actual bytes skipped.
*/
public long skip(long n)
throws IOException
{
return 0;
}
/**
* Returns true if this is a read stream.
*/
public boolean canRead()
{
return false;
}
/**
* Returns the read buffer.
*/
public byte []getReadBuffer()
{
return null;
}
/**
* Reads the next chunk from the stream.
*
* @param buffer byte array receiving the data.
* @param offset starting offset into the array.
* @param length number of bytes to read.
*
* @return the number of bytes read or -1 on end of file.
*/
public int read(byte []buffer, int offset, int length) throws IOException
{
throw new UnsupportedOperationException(String.valueOf(this));
}
/**
* Reads the next chunk from the stream in non-blocking mode.
*
* @param buffer byte array receiving the data.
* @param offset starting offset into the array.
* @param length number of bytes to read.
*
* @return the number of bytes read, -1 on end of file, or 0 on timeout.
*/
public int readNonBlock(byte []buffer, int offset, int length)
throws IOException
{
return readTimeout(buffer, offset, length, 0);
}
/**
* Reads the next chunk from the stream in non-blocking mode.
*
* @param buffer byte array receiving the data.
* @param offset starting offset into the array.
* @param length number of bytes to read.
*
* @return the number of bytes read, -1 on end of file, or 0 on timeout.
*/
public int readTimeout(byte []buffer, int offset, int length,
long timeout)
throws IOException
{
return 0;
}
/**
* Returns the number of bytes available without blocking. Depending on
* the stream, this may return less than the actual bytes, but will always
* return a number > 0 if there is any data available.
*/
public int getAvailable() throws IOException
{
return 0;
}
public boolean isEof() throws IOException
{
return false;
}
/**
* Returns the current read position of the underlying file.
*/
public long getReadPosition()
{
return -1;
}
/**
* Returns true if this is a writable stream.
*/
public boolean canWrite()
{
return false;
}
/**
* Returns true if the buffer should be flushed on every newline. This is
* typically only true for error streams like stderr:.
*/
public boolean getFlushOnNewline()
{
return false;
}
/**
* Sets the write encoding.
*/
public void setWriteEncoding(String encoding)
{
}
/**
* Writes a buffer to the underlying stream.
*
* @param buffer the byte array to write.
* @param offset the offset into the byte array.
* @param length the number of bytes to write.
* @param isEnd true when the write is flushing a close.
*/
public void write(byte []buffer, int offset, int length, boolean isEnd)
throws IOException
{
throw new UnsupportedOperationException(String.valueOf(this));
}
/**
* Writes a pair of buffer to the underlying stream.
*
* @param buf1 the byte array to write.
* @param off1 the offset into the byte array.
* @param len1 the number of bytes to write.
* @param buf2 the byte array to write.
* @param off2 the offset into the byte array.
* @param len2 the number of bytes to write.
* @param isEnd true when the write is flushing a close.
*/
public boolean write(byte []buf1, int off1, int len1,
byte []buf2, int off2, int len2,
boolean isEnd)
throws IOException
{
if (len1 == 0) {
write(buf2, off2, len2, isEnd);
return true;
}
else
return false;
}
/**
* Clears any buffered values in the write.
*/
public void clearWrite()
{
}
/**
* Seeks based on the start.
*/
public void seekStart(long offset)
throws IOException
{
throw new UnsupportedOperationException(getClass().getName());
}
/**
* Seeks based on the end.
*/
public void seekEnd(long offset)
throws IOException
{
throw new UnsupportedOperationException(getClass().getName());
}
/**
* Flushes buffered writes.
*/
public void flushBuffer() throws IOException
{
}
/**
* Flushes the write output.
*/
public void flush() throws IOException
{
}
/**
* Flushes the write output, forcing to disk.
*/
public void flushToDisk() throws IOException
{
throw new UnsupportedOperationException(getClass().getName());
}
/**
* Returns the Path associated with the stream.
*/
public Path getPath()
{
if (_path != null)
return _path;
if (_nullPath == null)
_nullPath = new NullPath("stream");
return _nullPath;
}
/**
* Sets the Path associated with the stream.
*/
public void setPath(Path path)
{
_path = path;
}
/**
* Returns a stream attribute.
*
* @param name the attribute name.
*
* @return the attribute value.
*/
public Object getAttribute(String name)
throws IOException
{
return null;
}
/**
* Sets a stream attribute.
*
* @param name the attribute name.
* @param value the attribute value.
*/
public void setAttribute(String name, Object value)
throws IOException
{
}
/**
* Removes a stream attribute.
*
* @param name the attribute name.
*/
public void removeAttribute(String name)
throws IOException
{
}
/**
* Returns an iterator of the attribute names.
*/
@SuppressWarnings("unchecked")
public Iterator<String> getAttributeNames()
throws IOException
{
return NullIterator.create();
}
/**
* Closes the write half of the stream.
*/
public void closeWrite() throws IOException
{
close();
}
/**
* Returns true if the stream is closed.
*/
public boolean isClosed()
{
return false;
}
/**
* Closes the stream.
*/
public void close() throws IOException
{
}
}